Interruption injection pump



Aug. 22, 1944. N. N. SKAREDOFF I INTERRUP'IION INJECTION PUMP OriginalFiled June 27, 1940 or EXPANSION a COMPRESSION POSITION OF PISTONPOSITION OF PISTON I N VEN TOR.

Patented Aug. 22, 1944 i Original application June 27, 1940, Serial No."and this appllcation'November I 125, 1942, Serial No.: 466,848 4 Claims.(o1. 103 -41 I:

on United 342,638. Divided TillS,'iS a divisional application Statespatent application, Serial No. 342,638,.filed H i June 27.119510, underthe. title-of Interruption injection pump and method to apply thesame.

This, invention relatesto a new method and new devices for eliminationin toto or in part of c the so-called detonation in internal combustionengines operating on a two or-four-st'roke Diesel cycle, and. onthe'Ottoj cycle using. fuel-injection pumps. 9 i

Thisinvention also is' designed-to improve the controlcof the combustionof -trial inside of a cylinder of an intern al combustion engine.

For theconvenience'ofthe description; this specification will refer to.a' single' cycle occurring duringthe operationoL-the engine. The wordinjection will indicate the individual injection occurring during thesaid cycle; The amount-of" quantity injected during-each cycle' will bere ferred to as the total his] charge or charge.-'-

ew York, N. Y., assignoroi" v, one -halfto George A Rubiss ow, New, YorkUNITED STATES "PATENT? This invention refers to an "interruptedinje'cthe. working cylinder. I

In the drawing, wherei-nli-ke reference char-= views, Figurel is adiagrammatical view of themessure variation in the cylinder duringcompression and powerstroke. v Figure 2 is a diagrammaticalrepresentation'of 1 the fuel pressure; during injection usingnormaiinjection cycle. 7 v

Figure 3 is a diagrammatical representation of I J fuel pressureduri-nginlection using interrupted 1 injectioncyclaw V l H V Figure 4 isa itudinalcross sectional'view' The total fuel charge, according to thisinvention, is to be divideddnto' two parts -the initial I injection andthe"main:injeotion"; the initial injection beinga fraction of thetotalfuel charge;-

comprising-the "remainder of the: fuel I and the main injection or theremainder of injection charge. i The interval :of time between thetermination of the initialinjection and the beginning of the maininjection, willbe referred to in this specification as the-interruptionof the injection, or-the injection interruption."

In'engines'operatingon a compression fuel injection self-ignitionDieselcycle, also called Diesel petrol) injection self-ignition the ballisticexhaust of burned gases known under Kadenacy system as more fullydescribed in U. S. A. Patents, Nos. 2,147,200;"2,281,585; 2,134.920;2.102.559; the injection is preferably to be divided intotwo parts,comprising a small initial injection followed by an interruption, aftertype cycle, or on a compression fuel (or two cycle using a the HQ(interrupted injection'cycl'e), and the-'- acters refer to like partsthroughout these'veral' of an injection pump'piston withparts broken-FieureS is across-sectionalview-'5 5' of IFigure 4. I 1 I Figures-6,7and 8arecross-sectional-views with parts broken, out showing variouspositions of:

valve'of the'pum'pr the groove on the rotary Figure-1diagrammatically-'represents -one of the main points of thisinventiomwherein the during part of one cycle is demonstrated. ''Thesequence of eventssinslde the'workingcylinder .curve AC represents anair cycleof an engine with the. top dead center of the piston marked.TDC... The curve IIG represents-the pressure;

variation inside of the working cylinder during curve of the normalinjection cycle, hereinafter designated as NIC represents the variationpressure inside of the working cylinder operating on v a normalinjection cycle;

which interruption the main fuel charge is in- 1 jected. Forenginesoperatingon a four or twov stroke. spark-ignition cycle, the injectionof the fuel charge may also be dividedinto an initial charge followed bythe interruption, whereafter the main charge may be injected.

The initial charge may be equal to, smaller,

or larger than the main injection. The period t of interruption may betimed in accordance with the kind' and/or amount of fuel employed, .Oneor more interruptions may be used, dividing the fuel charge accordinglyinto corresponding fractions. This applies to Diesel engines as well asto Otto cycle engine's. J

In a normal injection cycle, theinjection begins at a point marked BNI(beginning of'normal injection), and steadily continues until the pointI ENI (end of normal injectionl'is'reached. Due

.to the lag ofignition, the combustion startsto occur onlyat point BIC(beginning of internal ll combustion) able portion'of fuel has alreadyentered the com- During that interval, a considerbustion space, and whenthe ignition occurs, the

entire quantity of the fuel already present in the I engine to knock ordetonate.

combustion space, starts to burn at once atan' uncontrollable".- rate ofspeech thus producing an excessively rapid pressure rise which causesthe occurs near the top dead centerposition of the piston, in whichregion it can move only very slowly, the magnitude of pressure-attainedis also I Inasmuch as i this 1 considerably in excess of what the enginewas originally designed to produce. When the piston begins to move onits expansion stroke, the injection is practically completed, and thepressure drops rapidly.

When interrupted injection cycle (IIC) 'is applied, instead of normalinjection cycle (NIC), the fuel injection starts at a point BII(beginning of interruption injection), and continues until the entireinitial amount of fuel is injected, and stops at a point marked EII. Thepiston continues on its compression stroke and when the period of thelag of ignition has elapsed, this initial quantity of fuel begins toburn at a point marked BE on the diagram. As this point, the main,injection commences substantially at a point marked BMI and continuesuntil the total amount of fuel required is injected.

It is to be noted that one of the main aspects of this invention istheproviding of the said interruption, i. the interval during whichtheinitial fuel chargebeginsto, burn and'produces an open flame, intowhich the remainder of the fuel charge is then injected.

It is also to be noted that such an interruption can be chosen inaccordance with the characteristics of the engine; and the fuel used.Due to the fact that the main fuel charge, according to this invention,is injected into the open flame, the time required to ignite (lag ofignition) is reduced to such an extent, that no appreciable quantity offuel can accumulate in the combus-' =tigii-rspace without being burnedas fast as it The rateiof injection can be easily controlled byinjection mechanism to inject only so much fuel into the combustionspace as is necessary to maintain a certain pressure behind the recedingpiston during the expansion stroke. In this way. all undue stresses onan engine are eliminated,

and a-useful even working mechanism with smooth torque is obtained.

Since the pressure rise inside of the combustion spaceis, very slow andlimited in magnitude, no detonation can be produced. The injection is'terminated at'a point EII after which the con- --ventional expansionfollows.

The quantities of fuel injected are represented by the shaded areas, asfollows: KKINNI represents the amount of fuel injected 50 showing theamount of fuel delivered to the cylinder, and similarly represented byKKiNNi shown in Figure 1.

Figure 3 diagrammatically shows the IIC with shaded area 5| representinthe initial injection similar to KK1LL1 as shown in Figure 1, and area53 represents the main injection similar to MMIOOI, shown in Figure 1.The interruption is represented by interval 52 between the areas 5| and53.

Lines 54, 55 and 58 on Figures 2 and 3, represent diagrammatically therise and fall of fuel pressure in the compression chamber of the pumpbefore discharge pressure is reached, and after delivery valve isclosed.

It is to be noted that Figures 1, 2 and 3 are diagrammatical views, anddo not limit the relation between the quantities of fuel injectedinitially, and the timing employed for the termination of such initialinjection and the interval of the main injection, and also do not limitthe relation between the time of the injection and the position of thepiston at which the injection occurs. By way of example:

(1) The initial quantity, instead of being smaller than the maininjection, as shown in Figures 1 and 3, can be equal to, larger orsmaller than the main injection.

(2) The relations between the three time-intervals necessary for (l) theinitial injection, (2) the interruption, and (3) the main injection, arenot limited by the ratio shown diagrammatically in Figures 1 and 3, andcan be varied according to the type of engine and fuel employed,

Presuming, for instance, that the magnitude of the interruption intervalis governed by the speed of the engine and the ignition characteristicsof fuel used, then the interruption interval should be so approximatelyequal to, or slightly smaller than the ignition lag of the fuel used.This, however, 'does not limit the invention to any other arrangements.

Another example of arrangement of the said three timeintervals, may, forinstance, be as follows:

" For a Diesel engine having a total injection period of about 20degrees, and operating on a fuel with ignition lag amounting to 10degrees of crankshaft rotation at operating-speed, the initial injectionwill start about 14 degrees before top dead center TDC and then continueuntil about 10 degrees before TDC. It will'then be interrupted for'about 9 or 10 degrees with the main injection commencing about 1 degreebefore TDC and continued until the full amount of fuel is delivered intothe cylinder, depending upon the load of the engine. This is given byway of ex "ample. only, and does not limit the invention thereto.

The timing at which the initial and main in- ,jections are designed tooccur is also not limited Ito that shown on Figures 1 and 3 and can bevaried to produce the best results in accordance 'j with the type ofengineand fuel employed.

= This new-method is not limited to a single in- -terruption as shown inFigures 1 to '7 inclusive.

More than one interruption during a single cycle can be used. If severalinterruptions are used, the

'sifirst intervalmaxflfor instance, be longer than the i s'econdJonefthe-first initial charge equal to, greater or smaller than thesecondcharge; and the remaining fuel charge equal to. greater or smaller thanthe initial charge.

The open flame created by the initial interruption injection reduces thelag of ignition of the main fuel charge when it begins to arrive in thecombustion space, to such adegree that no appreciable amount of fuel canaccumulate in the combustion space without being ignited. The fuel isburned as fast as it enters the combustion space, giving accuratecontrol of the pressure inside the cylinder, and thereby offering asmooth and efficient operation of the engine.

One of the advantages of the interruption in- .jection consists in thatit offers the possibility of using a cheap fuel of a low cetane numberin high-speed engines without detonation or other harmful effects takingplace. By way of example: a modern high-speed Diesel engine will notsatisfactorily operate on a fuel having a cetane number below 60. Theinterrupted injection properly designed for fuel with a cetane number ofaround 20, for instance, will operate with equal efliciency and nodetonation, as if a high-grade fuel were being used, a fuel, forinstance, with a cetane number around 80. It must be pointed out that ifa high-grade fuel is employed such as cetane number 80, the interruptedinjection may not showany considerable improvement of performance,inasmuch as it is designed preferably to permit the operation of theengine on a low-grade fuel.

A practical realization of this invention is 11- lustrated in Figures 4,5, 6, 7 and 8, representing schematically a rotary-valve type pump suchas known, for instance, under the trade-mark X- Cell-O the X-Cell-Opump, converted to produce the interrupted injection.

For this purpose a groove 14 is provided parallel or at an angle to theleading edge 15 in the raised portion or land of the rotary valve 16, asshown in Figure 4. It is to be noted that groove 14 divides the land ofthe rotary valve into the sections Ti and 18, whereby when section 11 ofthe rotating valve 16 covers the suction port 19 of the given piston P,the fuel is prevented from flowing back to the suction chamber 80 and isdisplaced to the injector via, the spring loaded discharge valve 83,'bythe advancing piston P in the cylinder 8 I.

As soon as the groove" begins to register with the suction port 19 anopen passage is established between the pressure chamber 82 and thesupply chamber 80 by means of suction port 19 and groove 14. During thetime that groove 14 is in register with the port 19, the fuel isdisplaced back into the supply chamber 80, i. e. the interruption in thedelivery of fuel is produced as shown by Figure 7. Thereafter, as shownon Figure 8, with the rotary valve continuing to rotate, section 18 ofthe land covers the suction port 19, the fuel in the pressure chamber 82is again forced to the injector, thus beginning the main injection.

Having now particularly described and ascertained the nature of the saidinvention and the manner in which it is to be used, I declare that whatI claim is:

1. A fuel injection pump for internal combustion engine comprising anumber of pistons each reciprocating in its respective cylinder providedtherefor, a plurality of spring-loaded check valves, said valvesprovided to control each said cylinder, port provided in each saidcylinder to control the inlet of the fuel, at least one rotary valvehaving a cylindrical body with at least two lands, said rotary valvebeing located in the fuel supply chamber and controlling the inlet ofthe said fuel through each said port, each said land being separatedfrom the other by a groove open on the side leading to the said fuelsupply chamber, each said groove registering each said port one at atime and for a predetermined length of time, thereby establishing aninterrupted fuel injection controlled by the size and shape of each saidland and each said groove.

2. A fuel injection pump for internal combustion engine comprising anumber of pistons each reciprocating in its respective cylinder providedtherefor, a plurality of spring-loaded check valves provided to controleach said cylinder, a port provided in each said cylinder to control theinlet of the fuel, at least one rotary valve having a cylindrical bodywith at least two lands, said rotary valve being located in the fuelsupply chamber and controlling the inlet of the said fuel through eachsaid port, each .said land being separated from the other by a grooveopen on the side leading to the said fuel supply chamber, saidgrooveregistering each said port one at a time and for a predeterminedlength of time, thereby establishing an interrupted fuel injectioncontrolled by the size and shape of each said land and said groove, saidgroove being parallel to the edge of the leading land.

3. A fuel injection pump for internal combustion engine comprising anumber of pistons each reciprocating in its respective cylinder providedtherefor, a plurality of spring-loaded check valves, said valvesprovided to control each said cylinder, port provided in each saidcylinder to control the inlet of the fuel, at least one rotary valvehaving a cylindrical body with at least two lands, said 'rotary valvebeing located in the fuel supply chamber and controlling the inlet ofthe said fuel through each said port, each said land being separatedfrom the other by a groove open on the side leading to the said .fuelsupply chamber, said groove registering each said port one at a time andfor a predetermined length of time, thereby establishing an interruptedfuel injection controlled by the size and shape of each said land andsaid groove,

said groove being at an angle to the edge of the leading land.

4. A fuel injection pump comprising a body in which are provided severalcylinders each having a spring-loaded reciprocating piston, at least onefuel cylinder provided with a rotating control-valve, a suitable part ofsaid rotating control-valve being provided with at least one landdivided into two parts by a slot provided in said land; said slot beingopen only on the end leading to the fuel chamber provided in the area ofthe displacement of said land, a plurality of ports interconnecting eachof said cylinders with the said fuel cylinder whereby when the said landand the said slot register each of the said ports, an interruptedinjection of the character described is established.

-NIKOLAI N. SKAREDOFF.

